The subject matter disclosed herein relates to single photon emission computed tomography (SPECT), and more particularly to a technique for reconstruction of 3D source distributions in cardiac imaging using emission data.
A wide range of imaging techniques are known and currently in use, particularly for medical diagnostic applications. One such technique, SPECT, relies on the emission of gamma rays during the radioactive decay of a radioisotope (or radionuclide), commonly administered in the form of a radiopharmaceutical agent that can be carried, and in some cases, bound to particular tissues of interest. A SPECT scanner detects the emissions via a gamma camera that typically includes a collimator, a scintillator, and a series of photomultiplier tubes. The collimator allows only emissions in a particular direction to enter into the scintillator. The scintillator converts the gamma radiation into lower energy ultraviolet photons that impact regions (pixels) of the photomultiplier tubes. These, in turn, generate image data related to the quantity of radiation impacting the individual regions. Image reconstruction techniques, such as backprojection, may then be used to construct images of internal structures of the subject based upon this image data.
While such systems have proven extremely useful at providing high quality images with good diagnostic value, further refinement is needed. For example, SPECT imaging systems may use reconstruction techniques such as filtered backprojection or other techniques to reconstruct three-dimensional images. However such techniques, such as Maximum Likelihood Expectation Maximization (MLEM) or Block Sequential Regularized Expectation Maximization (BLREM), may not provide the desired performance and image quality and may be particularly sensitive to noise and the position of the subject.